Newb Question: Charging 12v Bank w/ separate 12v and 24v panels

MEN!

Solar Enthusiast
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Jul 7, 2020
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Hi guys,

My van currently has (4) 160W 12V panels separated into 2 different arrays (each going to its own charge controller - i have 2). For space reasons, i will be ditching (2) panels and replacing with (1) Panasonic 330W panel. So the (2) remaining 160W 12V panels will be wired in series in their own array on one charger. The (1) Panasonic 330W panel will be on its own, utilizing a EPEVER 40A MPPT charge controller. My battery bank is 12V composed of (2) 200Ah LifePO4 batteries.

Does charging my bank with two separate arrays of different voltage pose a risk? Anything I need to change first? I'm not sure about this Panasonic panel..it's not actually listed as a 12V or 24V. The 40A MPPT appears to be appropriately rated. The Panasonic 330W panels specs are as follows:

Nominal Maximum Power (Pmax):330 Watts
Maximum Power Voltage (Vpm):58.00 Volts
Maximum Power Current (Ipm):5.70 Volts
Open Circuit Voltage (Voc):69.70 Volts
Short Circuit Current (Isc):6.07 Amps

EPEVER 40A MPPT
40amps solar charge controller, Max input power 520W(12V); 1040W(24V) solar panner, Max. solar array Voc 100 V;

Thank you for any help
 

eXodus

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Jul 27, 2020
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792
The different voltage is only from the panel to the MPPT - after the MPPT the voltage should be the same again.

Just make sure that the MPPT voltages are configured the same. Otherwise one will stop charging before the other.
 

MEN!

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Just make sure that the MPPT voltages are configured the same. Otherwise one will stop charging before the other.
Wouldn't one MPPT need to stay configured for 12V and the other be switched to 24V?
 

eXodus

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Messages
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Wouldn't one MPPT need to stay configured for 12V and the other be switched to 24V?
isn't your battery 12V ? Where do you get the 24V from?

There are no "12V" or "24V" panels. That's marketing. Anything above 14V can charge a 12V battery and anything above 26V can charge a 24V battery.
Your Panasonic panel has 56V - so it can charger a 12V battery or 24V battery.
 

MEN!

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isn't your battery 12V ? Where do you get the 24V from?

There are no "12V" or "24V" panels. That's marketing. Anything above 14V can charge a 12V battery and anything above 26V can charge a 24V battery.
Yes, correct. My battery is 12V.

Okay my bad, I was thinking of the panel as '24V'. Thanks for your help
 

richard cabesa

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Mar 16, 2021
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You are doing fine with the different panels on different charge controllers. Just make sure to configure both controllers to have the same bulk/float voltages to your batteries.
I have 3 charge controllers (on different sets of panels) and a BtoB charger all parallel to the same bank and it has worked flawlessly for a 2-1/2 years now
 

MEN!

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So how do you have your panels setup? It seems likely that without a basic knowledge of your SCC’s input and output voltages, its likely in a “suboptimal” configuration.
Can you be a little more specific? Do you mean how do I have them connected, what are my charge controller settings…?
 

MisterSandals

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Nov 5, 2019
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Silicon Valley
Sorry, misread your OP. I thiught it was 4 panels + 2 panels + 2 panels + 1 big panel.

Looks like you got good info from everybody else.
 
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